Go to the Office app in question and go to the Options. From there, click on Advanced and make sure “”Ignore other applications that use Dynamic Data Exchange (DDE)” is UNCHECKED like below in my version of Excel 2016.

I’ve been using the beta build of Office 2016 and one of the nice new features that I’ve been getting use out of is the “Attach File” button. Before, you were prompted for a folder and file when clicking this button. In Outlook 2016, you are shown recent documents that you have saved. So if you work on Doc21.docx, save it, then go into Outlook and click ‘Attach File’… that file is the first one listed without needing to navigate around folders and finding your file! Nifty little feature. Screenshot below: